package com.gzsxy.JUC.pc;

/**
 * 线程之间的通信问题：生产者和消费者问题！
 * 线程交替执行 a b 操作同一个变量 num = 0
 * 传统模式    synchronized wait notifyAll
 */
public class A {
    public static void main(String[] args) {
        Data data = new Data();
        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    data.increment();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

            }
        }, "A").start();

        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    data.decrement();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

            }
        }, "B").start();

        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    data.increment();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

            }
        }, "C").start();

        new Thread(() -> {
            for (int i = 0; i < 10; i++) {
                try {
                    data.decrement();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }

            }
        }, "D").start();

    }
}

class Data {
    private int number = 0;

    //+1
    public synchronized void increment() throws InterruptedException {
        //如果这里用if判断那么在多个线程当中进来这个方法，if只判断一次，
        while (number != 0) {
            //等待
            this.wait();

        }
        number++;
        //通知其他线程，我+1完毕了
        System.out.println(Thread.currentThread().getName() + "=>" + number);
        //通过其他线程我+1完毕
        this.notifyAll();
    }


    //-1
    public synchronized void decrement() throws InterruptedException {
        while (number == 0) {
            //等待
            this.wait();


        }
        number--;
        //通知其他线程，我-1完毕了
        System.out.println(Thread.currentThread().getName() + "=>" + number);
        //通过其他线程我-1完毕
        this.notifyAll();
    }


}